Surgical instruments for various bone shaping or resection operations, required in the implantation of prosthetic devices, have been devised to assist orthopedic surgeons in accurately performing the necessary cutting steps.
One example of such instrumentation is U.S. Pat. No. 4,474,177 to Whiteside, disclosing a device and method which utilize an intermedullary rod for aligning a shaping tool(s) to make several angular resection cuts using a common reference axis precisely established by the rod.
Another example is the apparatus described U.S. Pat. No. 4,721,104 to Kaufman and Whiteside, which describes a femoral shaping apparatus employing a template having a straight slot therein for cutting a relatively deep recess for an intercondylar stabilizing housing of a knee implant. The patent, however, does not disclose a cutting guide having a curved track useful for forming a groove to accommodate a patellar track on such a prosthesis.
Heretofore it has been common practice for a surgeon to form a patellar track groove in a resected distal femur, if required, due to the nature of the particular knee prosthesis being implanted, by use of various cutting or abrading tools or instruments without aid of any type of locating or guiding instrument. In design and seating of a prosthesis it is important to retain the original patella/femoral joint line to avoid placing undue stress on the patella and its connective tissues.
U.S. Pat. application Ser. No. 462,268, filed Jan. 9, 1990 in the name of Coates, et. al, describes an improved system for accurate placement and cutting of a groove to accommodate a patellar track portion of a prosthesis to insure accurate seating of the prosthesis for long term wear and stability of a patellar prosthesis.
There still remains a need for using common surgical instrumentation to form both a groove and deep recess in the resected distal femur, respectively accommodating a patellar track and intercondylar stabilizing housing of the implant.